Field of the Invention
The invention generally relates to small scale base stations (femtocells), and more specifically to implementations of green femtocells.
Related Art
Femtocells are small scale base stations, typically installed by users, designed to enhance in-building cellular services. Femtocells typically are utilized within mobile phone networks, and generally cover smaller areas than traditional cellular macrocells. Femtocells allow service providers to extend service coverage and enhance capacity indoors, as well as to other areas where access would otherwise be limited or unavailable. However, under normal operating conditions, femtocells are constantly “ON,” meaning that a femtocell's transmitter is constantly transmitting both a broadcast channel (BCH) as well as a pilot signal. This constant transmission by the femtocells occurs regardless of whether any cellular handsets (UEs) are actively engaged on a call. Consequently, this constant transmission by the femtocells sometimes may cause interference with other wireless equipment such as WiFi, macrocells or other femtocell transmissions. Because the use of femtocells in residential areas is increasing dramatically, this constant transmission of the BCH and pilot by the femtocells creates additional concerns pertaining these residential deployments. For example, many individuals and groups are concerned about the potential health risks caused by the radiation associated with the continual transmission of signals by the femtocells, particularly in densely populated residential areas.
In accordance with existing cellular standards such as Global System for Mobile Communications (GSM), 2G, 3G or LTE, femtocells can be configured to act like macrocell base stations. In this configuration, femtocells generally consume a great deal of power which may not be justified, given the application. The constant transmission of the BCH and the pilot, associated with these conventional femtocells, also results in significant power consumption. This large power consumption renders a wide spread deployment of conventional femtocells relatively inefficient.
Thus, a need exists for a “green” femtocell that conserves power, limits radiation emissions and minimizes interference towards WiFi, macrocells, and/or other femtocells.
Embodiments of the invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number